﻿<!DOCTYPE html>
<html>
<head>
    <title>A Single Page Diagram</title>
  <!-- Copyright 1998-2021 by Northwoods Software Corporation. -->
  <meta name="description" content="A diagram that shows a sheet of paper; nodes cannot be dragged or resized beyond the edge of the sheet." />
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <script src="../release/go.js"></script>
  <script src="../assets/js/goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->
  <script id="code">
    function init() {
      if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this
      var $ = go.GraphObject.make;

      var pageSize = new go.Size(612, 792);
      var pageMargin = new go.Margin(10);
      var usableMargin = new go.Margin(10);
      var pageBounds = new go.Rect(-usableMargin.left, -usableMargin.top, pageSize.width, pageSize.height);
      var usableArea = pageBounds.copy().subtractMargin(usableMargin);

      myDiagram =
        $(go.Diagram, "myDiagramDiv",
          {
            fixedBounds: pageBounds.copy().addMargin(pageMargin),
            initialAutoScale: go.Diagram.Uniform,
            "animationManager.isInitial": false,
            "undoManager.isEnabled": true,
            "resizingTool.doMouseMove": function() {
              var e = this.diagram.lastInput;
              e.documentPoint = limitPoint(e.documentPoint);
              e.viewPoint = this.diagram.transformDocToView(e.documentPoint);
              go.ResizingTool.prototype.doMouseMove.call(this);
            },
            "resizingTool.doMouseUp": function() {
              var e = this.diagram.lastInput;
              e.documentPoint = limitPoint(e.documentPoint);
              e.viewPoint = this.diagram.transformDocToView(e.documentPoint);
              go.ResizingTool.prototype.doMouseUp.call(this);
            },
            "TextEdited": function(e) {
              var node = e.subject.part;
              node.ensureBounds();  // has been resized, compute its new bounds
              var pt = limitPoint(node.location);
              node.location = stayInFixedArea(node, pt, pt);
            }
          });

      // the background Part showing the sheet of paper;
      // it has the fixed bounds of the diagram contents
      myDiagram.add(
        $(go.Part, "Grid",
          {
            layerName: "Grid",
            position: pageBounds.position,
            desiredSize: pageSize,
            isShadowed: true,
            background: "floralwhite"
          },
          $(go.Shape, "LineH", { stroke: "lightgray", strokeWidth: 0.5 }),
          $(go.Shape, "LineV", { stroke: "lightgray", strokeWidth: 0.5 })
        ));

      // this function is the Node.dragComputation, to limit the movement of the parts
      // use GRIDPT instead of PT if DraggingTool.isGridSnapEnabled and movement should snap to grid
      function stayInFixedArea(part, pt, gridpt) {
        var diagram = part.diagram;
        if (diagram === null) return pt;
        // compute the document area without padding
        var v = usableArea;
        // get the bounds of the part being dragged
        var b = part.actualBounds;
        var loc = part.location;
        // now limit the location appropriately
        var x = Math.max(v.x, Math.min(pt.x, v.right - b.width)) + (loc.x - b.x);
        var y = Math.max(v.y, Math.min(pt.y, v.bottom - b.height)) + (loc.y - b.y);
        return new go.Point(x, y);
      }

      function limitPoint(p) {
        return new go.Point(Math.max(usableArea.left, Math.min(p.x, usableArea.right)),
                            Math.max(usableArea.top, Math.min(p.y, usableArea.bottom)));
      }

      myDiagram.nodeTemplate =
        $(go.Node, "Auto",
          {
            resizable: true,  // but limited by overrides of ResizingTool methods, above
            dragComputation: stayInFixedArea  // this limits the DraggingTool
          },
          $(go.Shape,
            { fill: "white", portId: "", fromLinkable: true, toLinkable: true, cursor: "pointer" },
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 8, editable: true },
            new go.Binding("text").makeTwoWay())
        );

      myDiagram.linkTemplate =
        $(go.Link,
          { relinkableFrom: true, relinkableTo: true },
          $(go.Shape),
          $(go.Shape, { toArrow: "OpenTriangle" })
        );

      myDiagram.model = new go.GraphLinksModel(
      [
        { key: 1, text: "Alpha", color: "lightblue" },
        { key: 2, text: "Beta", color: "orange" },
        { key: 3, text: "Gamma", color: "lightgreen" },
        { key: 4, text: "Delta", color: "pink" }
      ],
      [
        { from: 1, to: 2 },
        { from: 1, to: 3 },
        { from: 2, to: 2 },
        { from: 3, to: 4 },
        { from: 4, to: 1 }
      ]);
    }
  </script>
</head>
<body onload="init()">
  <div id="sample">
    <div id="myDiagramDiv" style="border: solid 1px black; width:100%; height:600px"></div>
    This pretends to show a sheet of paper with the diagram on it.
    Both the <a>DraggingTool</a> and the <a>ResizingTool</a> are constrained to keep the nodes within
    the area of the sheet of paper, minus the margins.
    The user can zoom and scroll/pan normally.
    There are several variables, such as <code>pageSize</code>, that govern how the diagram is set up.
  </div>
</body>
</html>